Sensors for detecting gases are used in different applications. Often, gas sensors are required to be highly sensitive and cost-effective to build as well as to use. As an example, gas sensors may be used in oxygen concentrators adapted for oxygen therapy in order to control process conditions.
Oxygen therapy is the administration of oxygen as a therapeutic modality. It is widely used for a variety of purposes in both chronic and acute patient care as it is essential for cell metabolism, and in turn, tissue oxygenation is essential for all physiological functions. Oxygen therapy should be used to benefit the patient by increasing the supply of oxygen to the lungs and thereby increasing the availability of oxygen to the body tissues, especially when the patient is suffering from hypoxia and/or hypoxemia. Oxygen therapy may be used both in applications in hospital or in home care. The main home care application of oxygen therapy is for patients with severe chronic obstructive pulmonary disease (COPD).
Oxygen may be administered in a number of ways. A preferable way of oxygen administration is by using a so called on demand generation of oxygen. Referring to this, commercial solutions, so-called oxygen concentrators or separators, respectively, are widely known. These oxygen concentrators mostly separate oxygen from an oxygen comprising gas, so that the oxygen is provided on demand, i.e. directly before use.
Known from EP 1 029 577 A2 is an apparatus for producing oxygen enhanced gas from air. According to this document, fractionators produce an oxygen enhanced gas for use in oxygen inhalation therapy. The fractionators include an air source for supplying air, and a plurality of columns for containing an adsorbent material for adsorbing nitrogen gas. Each of the columns has first and second ends. Air is directed from the air source to the column through the first open ends of the respective columns. A temperature sensor detects the temperature of the side wall of one of the columns. The fractionators changes the time for adsorption of nitrogen gas to the adsorbent material based on the detected temperature.
There is, however, still potential for improving the operating conditions of oxygen separation devices especially with regard to measuring oxygen purity.